1. Technical Field
The invention relates to a control circuit, a control device, a control method, and an image forming apparatus having the control circuit. Specifically, the invention relates to controlling an external apparatus connected via a signal line.
2. Related Art
A related control circuit controlling an external apparatus by connecting to the external apparatus is known. The related control circuit may be connected to the external apparatus via a signal line. One of a pull-up resistor and a pull-down resistor may be connected to the signal line, thus a voltage of the signal line can be stabilized in a non-communication time. In contrast, the pull-up resistor and the pull-down resistor may generate sink currents or source currents in the non-communication time, thereby increasing power consumption in the control circuit. In the related art, a resistor connected to the signal line is limited to the pull-up resistor and a voltage (on-voltage) equal to or higher than a threshold voltage is output from the control circuit to the signal line in the non-communication time, thereby suppressing the power consumption in the control circuit.